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Mariulka [41]
3 years ago
12

According to ohm's law what is the resistance of a light bulb if the applied voltage is 21 volts and the current is 3 amps?

Physics
1 answer:
Nady [450]3 years ago
6 0
Resistance = voltage/current = 21/3 = 7Ω
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The sound level measured in a room by a person watching a movie on a home theater system varies from 40 dB during a quiet part t
UNO [17]

Answer:

\alpha=-3.01dB

Explanation:

From the question we are told that:

Sound level intensity

 \triangle I=40dB-80dB

Generally the equation for  intensity level  is mathematically given by

 \alpha=10log_{10}(I/I_x)dB

Where

 I= Intensity measured

 I_x=Threshold\ of\ audibility

 I_x= 10-12 W / m2

 \alpha= 10 log10 \frac{I_1}{I_x} - 10 log10 \frac{}I_2{I_x}

 \alpha= 10 log10 \frac{I_1}{I_2}

 \alpha=10 log10\frac{40}{80}

 \alpha=-3.01dB

7 0
3 years ago
A steel piano wire, of length 1.150 m and mass 4.80 g is stretched under a tension of 580.0 N.
kaheart [24]

A steel piano wire, of length 1.150 m and mass of 4.80 g is stretched under a tension of 580.0 N.the speed of transverse waves on the wire would be  372.77 m/s

<h3>What is a sound wave?</h3>

It is a particular variety of mechanical waves made up of the disruption brought on by the movements of the energy. In an elastic medium like the air, a sound wave travels through compression and rarefaction.

For calculating the wave velocity of the sound waves generated from the piano can be calculated by the formula

V= √F/μ

where v is the wave velocity of the wave travel on the string

F is the tension in the string of piano

μ is the mass per unit length of the string

As given in question a steel piano wire, of length 1.150 m and mass of 4.80 g is stretched under a tension of 580.0 N.

The μ is the mass per unit length of the string would be

μ = 4.80/(1.150×1000)

μ = 0.0041739 kg/m

By substituting the respective values of the tension on the string and the density(mass per unit length) in the above formula of the wave velocity

V= √F/μ

V=√(580/0.0041739)

V =  372.77 m/s

Thus,  the speed of transverse waves on the wire comes out to be  372.77 m/s

Learn more about sound waves from here

brainly.com/question/11797560

#SPJ1

6 0
1 year ago
You walk into a darkened room and turn on a flashlight. You see an image of the flashlight reflecting off a plane mirror in fron
user100 [1]

Answer:

4.2 is the answer

Explanation

The image formed in a plane mirror is an equal distance behind the mirror as the object in front of it.

Step 1: the equation to this problem would be: 8.4/2

Step 2: 8.4 ÷ 2 = 4.2

6 0
2 years ago
In this example we will analyze the forces acting on your body as you move in an elevator. Specifically, we will consider the ca
dexar [7]

Answer:

The reading of the scale during the acceleration is 446.94 N

Explanation:

Given;

the reading of the scale when the elevator is at rest = your weight, w = 600 N

downward acceleration the elevator, a = 2.5 m/s²

The reading of the scale can be found by applying Newton's second law of motion;

the reading of the scale  = net force acting on your body

R = mg + m(-a)

The negative sign indicates downward acceleration

R = m(g - a)

where;

R is the reading of the scale which is your apparent weight

m is the mass of your body

g is acceleration due to gravity, = 9.8 m/s²

m = w/g

m = 600 / 9.8

m = 61.225 kg

The reading of the scale is now calculated as;

R = m(g-a)

R = 61.225(9.8 - 2.5)

R = 446.94 N

Therefore, the reading of the scale during the acceleration is 446.94 N

4 0
3 years ago
Statements about isotopes
Iteru [2.4K]

Answer:

Key Takeaways: Isotopes

Isotopes are samples of an element with different numbers of neutrons in their atoms.

The number of protons for different isotopes of an element does not change.

Not all isotopes are radioactive. Stable isotopes either never decay or else decay very slowly. ...

When an isotope decays, the starting material is the parent isotope.

Explanation:

8 0
3 years ago
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